Electromagnet cores having shading coils are known in the prior art. Such coils are desirable in A.C. electromagnets to diminish chattering and noise by preventing the flux from dropping to zero.
These coils, commonly made of copper, are pre-formed and the pre-forming process leaves much scrap as waste. A compound die first punches out a rectangular blank and then punches a rectangular aperture in the blank. The forming punch has a rectangular shell-like configuration which is subject to frequent breaking, requiring replacement, thus resulting in high cost tooling and tool maintenance. These coils must be affixed to the core in some manner and this involves extra assembly steps wherein the coil must be handled, placed on the core, and staked or cemented.